In what is emerging as the battle of the billionaires, Trump said he has banned every brand of whisky sold by William Grant & Sons from his resorts and hotels after Michael Forbes, his obstinate neighbour in Aberdeenshire, was voted Top Scot in a ceremony sponsored by the distiller's leading brand, Glenfiddich.

The closest resident to Trump's golf course, Forbes won the award last week after a public vote, beating the Olympic tennis gold medallist and US Open winner Andy Murray. Trump said that decision was "an insult to both Andy Murray and Scotland itself".

Trump claimed that William Grant & Sons, which broke through the £1bn sales barrier this year and owns several of the world's most popular whiskies, including Grant's, was jealous of his own inhouse single malt whisky brand.

The distillery sold more than one million cases of Glenfiddich, but Trump continued: "Glenfiddich should be ashamed of themselves for granting this award to Forbes, just for the sake of publicity.

"Glenfiddich is upset that we created our own single malt whisky using another distillery, which offers far greater products. People at our clubs do not ask for Glenfiddich, and I make a pledge that no Trump property will ever do business with Glenfiddich or William Grant & Sons.

"I hereby call for a boycott on drinking Glenfiddich products because there is no way a result such as this could have been made by the Scottish people."

After suggesting that the voting for Forbes had been fixed by "a small group of detractors" casting multiple votes, he continued: "Glenfiddich's choice of Michael Forbes, as Top Scot, will go down as one of the great jokes ever played on the Scottish people and is a terrible embarrassment to Scotland."

William Grant & Sons gave short shrift to Trump's criticisms, which he first aired on Twitter on Tuesday, insisting it had nothing to do with the voting for the award, which Glenfiddich has sponsored for 15 years.

It had never interfered with the outcome, it said, and insisted Forbes's victory should be respected.

"We understand that there may have been some confusion and misunderstanding concerning the structure and running of the Glenfiddich Spirit of Scotland Awards," the firm said in a statement.

"Top Scot is a totally open category in which the people of Scotland can vote for whomsoever they choose and Glenfiddich has no influence on this decision. [The] Top Scot may be one of that year's category nominees or may come from any walk of life. The person receiving the greatest number of votes, cast by the people of Scotland, wins the award."

It added: "In the history of these awards, we are not aware of the Top Scot award causing any offence or upset to anyone and it is not our intention to do so now. These awards were set up to give the people of Scotland a vote and we must respect their decision."